Pass-by-Pass Ambiguity Resolution in Single GPS Receiver PPP Using Observations for Two Sequential Days: An Exploratory Study

Ruijie Xi,Xiaolin Meng,Weiping Jiang,Qusen Chen,Caijun Xu,Panos Psimoulis

doi:10.3390/rs13183728

Abstract

“Pass-by-pass” or “track-to-track” ambiguity resolution removes Global Navigation Satellite System (GNSS) satellite hardware delays between adjacent undifferenced (UD) ambiguities, which is often applied in precise orbit determination (POD) for Low Earth Orbit (LEO) satellites to improve the accuracy of orbits. In this study, we carried out an exploratory study to use the “pass-by-pass” ambiguity resolution by differencing the undifferenced ambiguity candidates for two adjacent passes in sidereal days for a single Global Positioning System (GPS) receiver static Precise Point Positioning (PPP). Using the GPS observations from 132 globally distributed reference stations of International GPS Service (IGS), we find that 99.08% wide-lane (WL) and 97.83% narrow-lane (NL) double-difference ambiguities formed by the “pass-by-pass” method for all stations can be fixed to their nearest integers within absolute fractional residuals of 0.2 cycles. These proportions are higher than the corresponding values of network solution with multiple receivers with 97.39% and 91.20%, respectively. About 97% to 98% of ambiguities can be fixed finally on average. The comparison of the estimated station coordinates with the IGS weekly solutions reveals that the Root Mean Square (RMS) in East and North directions are 2-4 mm and is about 6 mm in the Up direction. For hourly data, it is found that the mean positioning accuracy improvement can achieve to about 10% after ambiguity resolution. From a dam deformation monitoring application, it shows that the fixing rate of WL and NL ambiguity can be closed to 100% and higher than 90%, respectively. The time series generated by PPP are also in agreement with the short baseline solutions.

Highlights

The Global Positioning System (GPS) is nowadays widely used in Earth scientific explorations, such as tectonic motion, glacial isostatic adjustment, monitoring strong or slow ground motion due to earthquakes [1] and volcanoes [2], and engineering applications, such as monitoring the health conditions of dams and bridges [3,4], and ground subsidence [5]
This study, we carried out an exploratory research of pass-by-pass ambiguity resolution method by differencing the satellite-related hardware delays
Ambiguity-fixed Precise point positioning (PPP) solutions for a single receiver can be obtained without offorming pass-by-pass method by differencing the satellite-related baselines ambiguity and applyingresolution pass-by-pass resolution strategy is candidates tested based on GPS observaware The delays betweenambiguity undifferenced ambiguity in the adjacent passes for tw tions from globally distributed stations of

Summary

Introduction

The Global Positioning System (GPS) is nowadays widely used in Earth scientific explorations, such as tectonic motion, glacial isostatic adjustment, monitoring strong or slow ground motion due to earthquakes [1] and volcanoes [2], and engineering applications, such as monitoring the health conditions of dams and bridges [3,4], and ground subsidence [5] In most of these applications, baselines are generally formed between. The baselines can assist the ambiguity resolution in un-difference (UD) modeling by mapping the UD ambiguities into a maximum set of independent DD-ambiguities In this case, the uncalibrated phase delay originating. The geophysical signals will be hard to extract or model in the realization of the reference frame and the dynamics of the earth

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Conclusion